REGION: Warming climate may dry up water supplies

Coastkeeper forum explores future of San Diego County water

The San Diego region is likely to see its water supply from the
Colorado River reduced 10 to 25 percent in coming decades, as
climate change reduces rainfall to the region and higher
temperatures cause more evaporation upstream, David Pierce, a
climate researcher with the Scripps Institution of Oceanography,
said Wednesday at the San Diego Coastkeeper's forum on the region's
water supply.

The "Signs of the Tide" forum in San Diego considered the status
of the region's water supply, how climate change may affect it, and
how local authorities and residents can use water more
efficiently.

Pierce said that in addition to dwindling shares of Colorado
River water, the region may face shortages from the State Water
Project, a network of aqueducts and pumps that transfers water from
Northern California rivers to other parts of the state.

As rising ocean waters intrude on the Bay Delta, shorter, warmer
winters may also limit the state's ability to tap the snowpack,
Pierce said. If snow melts quickly and early, he said, it may
outstrip reservoirs' capacity, leaving more run-off flowing into
the ocean.

"The changing timing (of snow melt) means we won't be able to
use our water as efficiently," he said. "We count on the snow to
act as another reservoir."

Declining water supplies will be coupled with population growth,
particularly in inland San Diego County, where the drier climate
typically results in higher water use, he said.

"In the next 20 to 30 years, it will come to a head," he said,
noting that the region will need at least that long to adjust to
those developments.

"Any change to the water infrastructure takes decades," he
said.

Bruce Reznik, former executive director of Coastkeeper, said the
region lacks a vision for addressing that dilemma, and said that
even the current water system is fragile.

"We are one earthquake away, we are one catastrophe away from
not being able to provide water," he said.

Reznik said that reclaiming wastewater would be a safe and
efficient way to boost the region's water supply.

Brook Sarson, who installs rainwater harvesting and water reuse
systems, said collecting rainfall is an inexpensive means of
reducing water demand. Such systems may be as simple as
disconnecting the spout on rain gutters to direct rainfall into
yards and away from the street, she said. More elaborate catchment
systems collect and store rainwater in barrels, then funnel it into
gardens, she said.

"If you rethink the way you landscape and create basins in the
soil, you can grow more for less," she said.